1. Field of the Invention
The present invention generally relates to dressing products such as a bandage or other sterile covering that is put on a wound to protect it from infection or further damage. More particularly, the present invention concerns a dressing product composed of fibres of a spinnable polymer, and a method and system for producing the dressing product, useful for covering haemostatic as well as exudative wounds.
2. Description of the Related Art
Dressing products, in the form of a ribbon or wick, are often used for moist wounds that produce exudates, for example, bedsores, post-operative wounds, and deep wounds such as cavities. Dressing products can also be used in intranasal surgery, in the upper airways of the nasal fossae, or for stopping nose bleeds with short wicks, which is also called tampons.
In making most prior art dressing products, consideration is often given to an alginate of a metal chosen from the family of polyvalent metals, except for magnesium, and, more particularly, a calcium alginate.
A wound causes a loss of substance or of biological fluid (blood or exudate). When applied to a wound, the prior art dressings that are made of calcium alginate fibres begin by absorbing the biological fluid which oozes, or exudes, the water molecules of the fluid collecting between the molecules of the alginate.
Once swollen by absorption, the dressing undergoes gel formation through ion exchange. In the case of calcium alginate fibres, these yield Ca2+ ions to the biological fluid, and the latter yields Na+ ions in return. This ion exchange, the principal mechanism of action, constitutes the factor triggering the activation of platelets, macrophages and fibroblasts, as manifested by activation of the physiological processes of haemostasis and tissue repair.
The haemostatic action is due to the mechanical pressure action created by the swelling during hydration and to the biological action resulting from this rapid and intense release of calcium ions, thus inducing platelet aggregation and stimulation of clotting factors. Moreover, the fibres constitute a matrix making it possible to structure and strengthen the network of the blood clot.
As the equilibrium between calcium and sodium establishes itself, the alginate fibres lose some of their crystalline structure, leading to gel formation of the fibres. The gel formation of the dressing ensures that it does not adhere to the underlying tissues. However, it damages and more generally affects the integrity of the mechanical structure of the dressing, e.g., a wick, so that the dressing cannot be removed from the wound in one piece and without pain.
The aforementioned undesirable features of the prior art dressings are directly related to the underlying production material and method. The prior art dressings are obtained from a continuous card ribbon which is cut to the desired length. The card ribbon is obtained from a card web which is passed through a static cone (the funnel of a whistle) whose function is to gather the fibres and to give the web a cylindrical shape. Two motorized press rollers or calenders allow the material to be pulled and its shape to be fixed, before the wicks or tampons are formed, placed in bags or containers and then in boxes.
In this prior art production method, the fibres constituting the ribbon do not present cohesion in the direction of width, which causes them to slide in the direction of length. The dressing therefore cannot be removed from wounds in its entirety and without causing pain.